Malabsorption & Chronic diarrhoea Flashcards

1
Q

Diarrhoea - differential diagnosis (8 categories!)?

A

4 I’s and 4 M’s

Infection: bacterial, viral and parasitic (e.g. Giardia)

Inflammatory (IBD)

Intoleance - lactose / disaccharide (i.e. osmotic diarhoea)

IBS

Malabsorption (Coeliac, SBO, short bowel syndrome, pancreatic insufficiency)

Metabolic / Endocrine (diabetic autonmic neuropathy, hyperthyroidism)

Medication induced (e.g. Metformin)

Malignancy (CRC, Calcinoid, Villous adenoma)

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2
Q

Diarhoea investigations?

A

For 4 I’s

Stool culture, MCS, viral NAAT, OCP, C.diff.

Lactose tolerance test / lactose hydrogen breath test

ASCA/ANCA/Faecal calprotectin/Colonoscopy

For 4 M’s

Coeliac serology (TTG + IgA)

HBA1C, OGTT (if not known to be diabetic)

24h urine catecholamines & metanephrine (Phaeo)

24H urine 5-HIAA (Carcinoid)

TFT (Hyperthyroidism)

Finally colonoscopy to look for malignancy, IBD, microscopic colitis.

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3
Q

Symptom to ask about in taking history for patient with malabsorption? (5)

A

Steatorrhoea - offensive, bulky, pale stools

Weight loss

Skin rash (dermatitis herpetiformis - coeliac)

Symptoms of protein deficiencies - oedema

Symptoms of Minerals & Vitamin deficiencies (BDK):

  • Anaemia (Iron def, B12 - megabloblastic)
  • Glossitis (sore tongue), Angular stomatitis (red/swollen patches in the corners of the mouth) - Vitamin B def
  • Peripheral neuropathy - Vit B12 or B1
  • Bone pain (osteomalacia) - Vit D def
  • Bruising (Vit K def)
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4
Q

Risk factors for malabsorption? (8)

A

Remember that coeliac disease, chronic pancreatiits and previous gastric surgery account for 60%

  1. Previous gastric syrgery/bowel surgery (e.g. ileal resection)
  2. Crohn’s disease
  3. Pancreatic & Liver disease - ask about ETOH
  4. FH of coleliac or IBD
  5. Radiation
  6. Drugs (cholestyramine)
  7. Diabetes
  8. HIV
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5
Q

Malabsorption examinaiton?

A

Inspection: cachexia, pallor, bruising, oedema, rash, TPN?

BMI (<20)

Hands: signs of CLD, pallor of palmar creases

Neck: lymphadenopathy (lymphoma a/w coeliac)

Eyes: pallor

Mouth: glossitis, angular stomatitis (B group def)

Abdo: scars (gastric surgery), splenomegaly (lymphoma in coeliacs)

Legs: PN (b12/thiamine def), Subacute combined generation of the SC

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6
Q

DDx for malabsorption (7+ causes)

A

Coeliac disease

Gastric / bowel surgery (e.g. ileal resection)

Chronic pancreatitis

GI disease: Liver disease, IBD, infection (e.g. Giardia)

Systemic disease: diabetes, HIV

Drugs: alcohol & cholestyramine

Radiotherapy

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7
Q

What is your approach to investigating malabsorption?

A

Demonstrate malabsorption

  • Malabsorption “big 6”:
    • Iron studies,↑INR, ↓Ca, ↓cholesterol, ↓carotene, +ve Sudan stain of stool for fat (good screening test for steatorrhoea)
    • faecal fat estimation (over 3d) > 7g /d is abnormal (not widely available- alternative is faecal estalase) - greatly raised (>40g/d) strongly suggest pancreatic disease
    • Glucose or lactulose breath hydrogen test (for SBO)

Evaluate consequences

  • Anaemia: micro (iron), macro (B12), normo (chronic disease)
  • Albumin, folate, B12, CMP, ALP
  • Fat soluble vitamins A, D, E, K (INR)

Identify cause

  • Coeliac screen: TTG, IgA, anti-endmysial Abs
  • AXR: blind loops (SBO), pancreatic calcification
  • CT pancreatic protocol/MRCP/EUS - chronic pancreatitis
  • Gastroscopy + SB biopsy + duodenal aspirate for histology, parasites and bacterial growth → villous atrophy (coeliac), abnormal culture (SBO), clubbing + flattening of villi (Whipples), +ve PAS for macrophages (Whiples)
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8
Q

Investigation for malabsorption - gastroscopy + duodenal biopsies show subtotal villous atrophy. What are DDx other than coeliac disease? (5)

A

Tropical sprue (remember that TTG is also the most useful test for sprue)

Giardiasis

Lymphoma

Hypogammaglobulinaemia

Whipple’s (diarhoea, abdo pain, migratory non-deforming arthritis)

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9
Q

What is your approach to managing a patient with chronic diarrhoea & malabsorption?

A

Goals

  • Treat the underlying disease
  • Manage accompanying diarrhoea
  • Correct nutrient deficits
  • Optimise QOL

General managemen as follows.

Confirm dx & investigate for potential causes (A). Screen & treat depression.

T: Non-pharmacological

  • Dietary changes: Avoid caffeine (no more than 1/d), sweatened drinks, fruit juices and sorbitol containing gums (worsens diarhoea due to osmotic effects, especially where patient has no colon or very short length.
  • Fat restriction → reduces diarrhoea as unabsorbed FA induces secretory diarrhoea in colon

T: Pharmacological

  • Medium-chain triglyceride (MCT) supplements (compensates for calories lost due to the dietary restriction)
  • Fat-soluble vitamin supplements
  • ORS to prevent dehydration
  • Symptomatic treatment: loperamide

Involve dietician, seek Gastroenterology consult.

C: Screen for complications - regular DEXA to screen for metabolic bone disease & osteoporosis (fat malabsorption is risk factor) and fractures.

Disease specific tx

  • Gluten free-diet (Coeliac)
  • ABx (SIBO, Whipple’s)
  • Cholestyramine / cholestipole (bile salt malabsorption)
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10
Q

What is the test of choice to screen for coeliac disease when patient have IgA deficiency?

A

DGP - serum IgG Deaminated Gliadin Peptide

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11
Q

How would you manage coeliac disease and how would you monitor the patient? (5)

A

Gluten-free diet (wheat, barley, rye) + education/counselling + Dietician

Pneumococcal vaccine (due to hyposplenism in coeliac)

Monitor TTG 3-6 months (should normalise)

Consider re-biopsy duodenum in 3 months to confirm histological healing

  • Lack of healing/response may indicate alternative diagnoses or refractory sprue (which may respond to steroids) or lymphoma (T-cell enteropathy)

Osteoporosis screening

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